Monday theme 4 1630 1645 small briefing room mujica

1. Potential establishment of hymenopteran parasitoids for
classical biocontrol of the leafminer fly Liriomyza huidobrensis in
potato-based cropping systems
N. Mujica, P. Carhuapoma and J. Kroschel
DCE Crop Systems Intensification and Climate Change (CSI-CC)
10th Triennial Conference of the African Potato Association, Oct. 9-13, Ethiopia

2. Outline
Introduction
• L. huidobrensis as important native pest in Peru and an invasive
damaging pest in horticultural crops in Africa
• Selection of parasitoids for classical biocontrol
Potential establishment and control efficacy analysis
• Parasitoid phenology modeling and potential distribution assessment
using ILCYM
Establishment and control efficacy mapping results
• Examples of three parasitoid species
Conclusions

3. • Center of origin in the Neotropics; reported from more than 66 countries
• Very polyphagous pest: 220 plant species
Leafminer fly, Liriomyza huidobrensis
Countries with reported establishment Protected crops
= Center of origin
Introduction

4.  Pest resistant to many insecticides
 Emergence of new pests
 Negative effects on the agro-
ecosystem and human health
 Reduction or elimination of beneficial
insects
Intensive use
of pesticides
0
6
12
18
24
30
36
42
48
tm/ha
without insecticide
with insecticide
Peruvian potato varieties
30-60% yield loss
77.2
13.9
0
20
40
60
80
100
unsprayed farmer fieldParasitism(%)
Leafminer fly, Liriomyza huidobrensis

5. Liriomyza huidobrensis, a devastating pest in
horticultural crops in Kenya
Two projects funded by BMZ
Phase II (2010-2013):
Expanding the rational and biological control of invasive Liriomyza
leafminer flies to major horticultural production systems of East Africa
Phase I (2006-2009):
Tackling Liriomyza leafmining flies: invasive pests of global proportions.
Output 3: Complementary parasitoids studied, introduced, and released in Kenya
Output 2: The potential for classical biocontrol for leafminer flies assessed, host
specific parasitoids introduced, and their impact established in target countries.

6. Distribution of main leafminer fly parasitoid species
in the Neotropical region
Halticoptera
arduine
Chrysocharis
flacilla
Phaedrotoma
scabriventris
Parasitism and host feeding

7. Distribution and abundance of the main leafminer fly
parasitoid species in Peru
<30%
30-60%
>60%
Chrysocharis flacilla
Phaedrotoma scabriventris
Relative abundance (%):
Lowland
(0-500 m asl)
Highland
(2000-3900 m asl)
Halticoptera arduine
Species have different environmental preferences!

8. Characteristics of parasitoids used for classical
biocontrol of L. huidobrensis in Africa
Parasitoid
species
Parasitic
strategy
Ecological amplitude
(0- 4000 masl)
Parasitism on
L. huidobrensis
No. of LMF
host species
Halticoptera
arduine
larvae-pupae
Lowland coast (Chile, Peru) to
Andean highland (Argentina,
Peru).
35.0 - 72.9% 17
Chrysocharis
caribea
larvae-pupae
Lowland coast (Argentina,
Chile, Colombia, El Salvador,
Mexico, Peru and Uruguay) to
Andean highland (Argentina,
Colombia, Ecuador and Peru)
30-55% 46
Phaedrotoma
scabriventris
larvae-pupae
Lowland areas (Argentina,
Brazil, Chile, and Peru) and
highland (Argentina , Peru)
20-51.6% 20
The wide adaptation of these species shows great potential for classical
biocontrol of leafminer flies in other countries and regions

9. Classical biocontrol of L. huidobrensis in Africa
Objective
To estimate the potential establishment
and control efficacy of H. arduine, C.
flacilla, and P. scabriventris for regions
with a middle to high establishment risk
index of its host L. huidobrensis in
potato-based production systems of
Africa under current (year 2000) and
future (year 2050) climate change
scenarios.

10. Pest risk mapping using ILCYM
Life-table studies
A constant and fluctuating
temperatures: oviposition, survival
time, development time, mortality
Model validation
Temperature-based
phenology models
Modelbuilder
Development rate and time Survival rate, oviposition, mortality
Indices
PEI GI AI
Mapping
PEI=
∑𝑖𝑖=1
365 �𝑅𝑅𝑅𝑅𝑖𝑖 /365
𝑚𝑚𝑚𝑚𝑚𝑚( �𝑅𝑅𝑅𝑅𝑖𝑖)
∑𝑖𝑖=1
365
365 /�𝐺𝐺𝐺𝐺𝑖𝑖
365
GI=
log10 �
𝑖𝑖=1
365
̂𝜆𝜆𝑖𝑖AI=
Potential distribution at global, regional and
local level
Future climate: 2050
With and without crop shapes
Current climate: 2000
(1950-2000: www.worldclim.org/) Down-scaled data SRES-A1B, IPCC (2007):
http://gisweb.ciat.cgiar.org/GCMPage
(www.cipotato.org/ilcym)
Simulation of life-table
parameters
Net reproduction rate, generation time
0 10 20 30
50
100
50
100
150
0 10 403020 0 10 20 30
0.00
0.08
0.04
1.25
1.15
1.05
0.95
10 20 30 40
0
150
100
50
0 10 20 30 40
intrinsic and finite rate of increase, double time
Mapping parasitoids potential etablishment and
control efficacy using ILCYM

11. A successful establishment (EI>0.95) of the three parasitoid species can be expected in most African
countries under the year 2000 temperature conditions.
Parasitoids will maintain a high establishment potential (EI>0.95) under climate change temperature
scenarios for the year 2050
Potential regional establishment and distribution in Africa
Halticoptera arduine
Chrysocharis flacilla
Phaedrotoma
escabriventris
(displayed for potato production regions of Africa with an ERI>0.7 of its primary host Liriomyza huidobrensis)
2000 2050 Index change (2000-2050)
Results

12. Potential regional abundance in Africa
The GI for the year 2000 estimates between 11–22 and 5-13 generations/year in tropical and
subtropical African regions, which is in the same range as of its host L. huidobrensis.
Predictions for the year 2050 climate change scenario estimate an increase of 1–3 generations per
year for almost all Africa for the three species.
Halticoptera arduine
Chrysocharis flacilla
(displayed for potato production regions of Africa with an ERI>0.7 of its primary host Liriomyza huidobrensis)
2000 2050 Index change (2000-2050)
Phaedrotoma
escabriventris

13. Conclusions
 All three exotic parasitoids have a good potential to establish and
successfully control the leafminer fly L. huidobrensis in potato
production regions of Africa, in which the pest is causing significant
economic damage and where efficient natural parasitoids are
currently absent.
 Our predictions are in accordance with the successful introduction
and establishment of H. arduine, C. flacilla, and P. scabriventris in
cropping systems at different altitudes of Kenya.
 ILCYM is a new support tool to identify suitable release areas for
natural enemies and to project its potential efficacies to control pests
in a given environment according to the prevailing temperature.

14. New publication
Pest Distribution and Risk Atlas for Africa
Potential global and regional distribution and abundance of agricultural and
horticultural pests and associated biocontrol agents under current and
future climates

15. The first author